Synthesis and characterization of a new polymer support for a metallocene catalyst

Article abstract of DOI:10.1016/S0040-4020(02)00325-3

The synthesis of a novel polymer support and its use for the attachment of a metallocene catalyst is described in detail. The support was prepared by solid-phase synthesis from functionalized beads by the introduction of a spacer chain followed by the att

Full text of DOI:10.1016/S0040-4020(02)00325-3

TETRAHEDRON
Pergamon
Tetrahedron 58 72002) 3ꢀ85±3ꢀ92
Synthesis and characterization of a new polymer support
for a metallocene catalyst
a,p
Anthony G. M. Barrett and Yolanda R. de Miguel
b
a
Department of Chemistry, Imperial College of Science, Technology and Medicine, South Kensington, London SW7 2AY, UK
b
Department of Chemistry, King's College London, Strand, London WC2R 2LS, UK
Received 18 January 2002; accepted 14March 2002
AbstractÐThe synthesis of a novel polymer support and its use for the attachment of a metallocene catalyst is described in detail. The
support was prepared by solid-phase synthesis from functionalized beads by the introduction of a spacer chain followed by the attachment of
an alkylated cyclopentadienyl ligand. The characterization of the resulting resin-bound ligand and catalyst was achieved by using a wide
range of analytical techniques for on-bead analysis. The supported titanocene complex exhibited moderate catalytic activity in the
polymerization of ethylene. q 2002 Elsevier Science Ltd. All rights reserved.
1. Introduction
2. Results and discussion
In recent years, there has been rapid growth in the develop-
ment of novel polymer-supported compounds, such as
The ®rst objective of our investigation was to develop a new
support 6 with alcohol functionality 7Scheme 1) that would
contain a ¯exible spacer chain. This chain would consist of
methylene and ethylene glycol units, and would be cova-
lently attached to the resin backbone via a stable C±C bond.
The metallocene catalyst could be immobilized onto poly-
1
supported catalysts, reagents and scavengers. These
insoluble species allow for rapid and simpli®ed puri®cation
procedures and their use has become widespread in solu-
2
tion-phase organic synthesis and combinatorial chemistry.
Research in this ®eld has also led to a greater demand for
4
styrene in a number of ways, however, we chose to use the
covalent attachment of the metal catalyst via the h -cyclo-
3
polymeric supports that can withstand harsh reaction
5
conditions. These can be prepared by co-polymerization
of functionalized monomers or by post-polymerization
modi®cation of existing resins. One of the most active
areas of research in the ®eld of supported catalysis is the
pentadienyl ligand. Therefore, our ultimate objective was to
prepare a novel polymer-supported cyclopentadienyl ligand
9, by derivatization of the alcohol resin 6, which would be
useful as a support for transition metal catalysts. This new
ligand would be used to support the titanocene complex
and lead to the generation of a new supported ethylene
polymerization catalyst.
4
immobilization of catalysts for ole®n polymerization. The
earliest supported metallocene catalysts developed for
ethylene polymerization were based on silica particles, but
this is not an ideal support for these catalysts due to the free
hydroxyl groups on the surface which can lead to catalyst
deactivation. The development of polystyrene-bound
ethylene polymerization catalysts is currently an area of
considerable interest, and many recent reports have concen-
trated on well-de®ned polystyrene-supported catalysts for
The preparation of the novel polymer support 6 required the
synthesis of a suitably functionalized spacer chain 3a. Its
preparation was carried out in solution by monoprotection
of tetraethylene glycol with dihydropyran 1a, followed by
deprotonation of the resulting alcohol 2a and treatment with
excess 1,5-dibromopentane 7Scheme 1). The desired tetra-
hydropyranyl-protected bromide spacer 3a could be easily
prepared in large quantities and was obtained in good yield.
Its attachment onto the polystyrene support was achieved by
alkylation with polystyryllithium 4, which was in turn
5
ole®n polymerization. Herein we report our detailed studies
on a novel synthetic route to prepare a polymeric support
and demonstrate its use for the attachment of an ethylene
polymerization catalyst.
6
ꢀ
prepared by a previously reported method from polystyryl
bromide by lithium±halogen exchange. The lithiation step
could be monitored by bromine analysis of the beads 5a.
However, the need to determine the loading level of the ®nal
alcohol resin 6 7upon deprotection of 5a) led to the develop-
ment of a novel naphthyl-substituted tetrahydropyranyl
Keywords: polystyrene resin; polymer support; solid-phase organic syn-
thesis; supported metallocene catalyst; ethylene polymerization.
Corresponding author. Tel.: 144-20ꢀ-594-5ꢀ66; fax: 144-20ꢀ-594-
5805; e-mail: agmb@ic.ac.uk
p
0040±4020/02/$ - see front matter q 2002 Elsevier Science Ltd. All rights reserved.
PII: S0040-4020702) 00325-3

3ꢀ86
A. G. M. Barrett, Y. R. de Miguel / Tetrahedron 58 +2002) 3785±3792
2 2 2 3 2 2 2 2 5
Scheme 1. Reagents and conditions: 7a) HOCH 7CH OCH ) CH OH, CSA, CH Cl ; 7b) NaH, THF, Br7CH ) BR; 7c) 4, PhMe, 658C, 24h; 7d) CSA, THF,
H
2
O, D; 7e) 4-O NC SO Cl, pyridine, CH Cl ; 7f) 8, THF. All reactions carried out at room temperature unless otherwise noted.
2
2
6
H
4
2
2
ether protecting group 1b 7Scheme 2) that would allow
quantitative monitoring of the deprotection step by UV
spectroscopy.
2b and selective monoalkylation of the 1,5-dibromopentane
was achieved as before in moderate yield 754%) to give the
desired naphthyl-containing bromide spacer 3b 7Scheme 1)
which was treated with polystyryllithium 4 to give the
protected intermediate 5b. The cleavage of the protecting
group initially resulted in the formation of a mixture of
dihydropyran 1b and hydroxy-tetrahydropyran 1d, which
was treated with ethanol in order to force the complete
conversion of both species to adduct 1e. This process was
easily monitored by GC±MS, while UV spectroscopy of the
®nal cleaved species 1e was used to estimate the loading of
the alcohol resin 6. At this stage, FT-IR microspectroscopy
was used to detect the presence of the alcohol group in the
8
The palladium-catalyzed arylation of dihydropyran 1a to
give the desired naphthyl derivative 1b was investigated.
This reaction gave a 1:1 mixture of regioisomers, 1b and
1
c, which were separated by column chromatography.
However, the optimized synthetic route involved treatment
of the mixture 7without the need for separation) with tetra-
ethylene glycol to yield the intermediate 2b, in high yield
over the two synthetic steps. Deprotonation of the alcohol
1
3
1
resin 6. In addition, the C and H Gel Phase MAS NMR
spectra of this resin contained the expected peaks at d ꢀ1
and 3.8 ppm, respectively, for the ethylene glycol moiety.
The nosylate derivative 7 was successfully prepared from
the alcohol beads 6 7Scheme 1) by two sequential treatments
with excess 4-nitrobenzenesulfonyl chloride. Examination
of these beads by single bead FT-IR microspectroscopy
showed the appearance of two new peaks, due to the nitro
group, as well as disappearance of the hydroxyl peak. The
reaction progress could therefore be monitored by removal
Scheme 2. Reagents and conditions: 7a) 1-lodonaphthalene, 2 mol%
7Ph
3 2
P)
Pd7OAC)
2
, Et
Cl
3 2 2 2 3 2
N, 1008C, 48 h; 7b) HOCH 7CH OCH ) CH OH
7
TEG), CSA, CH
2
2
.

A. G. M. Barrett, Y. R. de Miguel / Tetrahedron 58 +2002) 3785±3792
3ꢀ8ꢀ
color) at 2ꢀ88C to the hindered resin-bound diene 9 resulted
in decoloration of the reagent and formation of the
supported adduct 11a. This conversion could be followed
by % nitrogen microanalysis and FT-IR microspectroscopy
7appearance of a new carbonyl peak). A solution model
experiment was carried out by treating pentamethylcyclo-
pentadiene with Cookson's reagent 10 in the solution phase
to yield the corresponding Diels±Alder adduct 11b, which
was fully characterized.
The loading level value for resin 9 obtained by derivati-
zation with Cookson's reagent 10 was not identical, but
was in the same range as the loading level which had
been estimated from the nosylate displacement reaction
70.21 mmol g ). This disagreement was probably due to
the indirect nature of both methods of quantitation, and
the possibility of some side reactions in the derivatization
of 9 with the Cookson's reagent 10.
Scheme 3.
of sample beads from the reaction vessel, followed by
washing with dichloromethane and drying prior to IR
spectroscopic examination. Microanalysis 7% nitrogen)
was also used to determine the extent of conversion and
the loading level 70.21 mmol g ). The reaction of the
nosylate resin 7 with the ethyl7trimethyl)cyclopentadienyl
anion 8, freshly prepared by deprotonation of the alkylated
2
1
2
1
Finally, the polymer-anchored cyclopentadienyl ligand 9
was used to support a titanocene dichloride complex 12
7Scheme 4). Firstly, the resin-bound ligand 9 was deproto-
nated with methyllithium, followed by treatment of the
anion with cyclopentadienyltitanium trichloride to give the
desired product 12. The titanium content of the beads was
determined using inductively coupled plasma-atomic
emission spectroscopy 7ICP-AES) and this allowed the esti-
9
cyclopentadiene with sodium hydride, was easily moni-
tored by FT-IR 7disappearance of the nitro peaks) and
microanalysis 70% nitrogen). The polymer-bound peralkyl-
ated cyclopentadienyl ligand 9 was thus obtained. It was
initially assumed that all the nosylate had been displaced
by the anion, so there would be an equivalent loading of this
2
1
ligand 70.21 mmol g ), however a derivatization reaction
was also studied in order to con®rm this result.
2
1
mation of the loading level of the catalyst 70.0ꢀ mmol g ).
The diffuse re¯ectance far-IR spectrum of the resin-bound
catalyst 12 7compared with that of the starting resin 9)
The loading level of the cyclopentadienyl resin 9 was
indirectly estimated by derivatization with Cookson's
reagent10 10 7Scheme 3) to give the Diels±Alder adduct
2
1
showed new sharp peaks in the region of 200±400 cm ,
which are typical for Ti±Cl stretches. X-Ray photoelectron
spectroscopy of a single bead showed a peak for the Ti 2p 7at
1
1a. Addition of the highly reactive dienophile 10 7red
4
5ꢀ.5 eV) which is identical to that reported for other
1
1
titanocene dichloride complexes. This was good evidence
that the structure of the species on the polymer was indeed
analogous to the homogeneous catalyst. Scanning electron
microscopy 7SEM) showed that the overall condition of
the beads 12 was excellent. The chemical composition of
the beads was also con®rmed by X-ray energy dispersive
spectroscopy 7X-EDS) of clusters of beads. Analysis of
the sample showed the presence of chlorine 7Cl K lineˆ
a
2
.6 keV) and titanium 7Ti K lineˆ4.5 keV) and the ratio
a
of Cl/Ti was roughly 2:1; in agreement with the expected
catalyst structure.
Finally, this resin-bound complex 12 was tested for catalytic
activity in the polymerization of ethene 7Scheme 4). The
polymer-supported titanocene dichloride 12 was ®rst treated
with a large excess of methylalumoxane co-catalyst 7MAO)
in toluene, to give the reactive catalytic species. Upon
addition of ethylene gas, the formation of polyethylene
was immediately observed. The activity per bar per hour
was estimated to be 41 g PE/mmol catalyst, which was not
as high as for previously reported catalysts. An interesting
Scheme 4. Reagents and conditions: 7a) MeLi, THF; 7b) CpTiCl
7c) MAO, PhMe, ethane; 7d) HCl, MeOH.
3
, PhMe;

3ꢀ88
A. G. M. Barrett, Y. R. de Miguel / Tetrahedron 58 +2002) 3785±3792
observation was the presence of noodle-like polyethylene
chains emanating from the beads that could be seen in the
mixed and the resulting solution was poured over the sample
00
onto a 1 mount and allowed to set at room temperature for
48 h. It was ground gently using 1200 SiC paper and
polished with 3 mm£1 mm diamond polish, washed with
methanol and dried.
1
2
SEM image of the product. Kaminsky's work on the coat-
ing of cellulose with polyethylene has also described this
noodle-like morphology. GPC analysis of the polymer was
also performed, by extracting the polyethylene with
trichlorobenzene at 1608C, and showed a molecular weight
Cyclopentadienyl titanium trichloride was obtained from
Aldrich and used and stored in a glove box. Polystyryl
peak at ꢀ34,000 7M 358,000, Mw 8ꢀ2,000) and a poly-
n
2
1
dispersity value 7M /M ) of 2.4. The M and polydispersity
w
bromide was obtained from Fluka 71.2±1.3 mmol g ,
ꢀ.8% Br, 100±400 mesh, 2% DVB). Cookson's Reagent
10 was purchased from Aldrich. Ethyltrimethylcyclopenta-
n
n
values were similar to those obtained from the soluble
titanocene dichloride catalyst 7M 400,000; M /M 2).
n
w
n
9
diene was prepared by the literature procedure. All solvents
and reagents were puri®ed by standard procedures.
3. Conclusions
4
.1.1. 3,6,9,12-Tetraoxa-12-+2-tetrahydropyranyl)dodecan-
1-ol +2a). 3,4-Dihydropyran 1a 76.28 g, ꢀ5 mmol) and tetra-
ethylene glycol 765 mL, 3ꢀ6 mmol) in CH Cl 7200 mL)
This paper reports the synthesis of a spacer-modi®ed
polymer support with alcohol functionality 6 and its use in
the preparation of a new polymer-bound peralkylated cyclo-
pentadiene ligand 9. This new support was also used to
covalently attach a metallocene catalyst 12 that was
successful in ethylene polymerization. Many new analytical
techniques for on-bead characterization were used and some
novel monitoring methods for solid-phase reactions, such as
the UV-active tetrahydropyranyl ether protecting group,
were also developed.
2
2
were cooled to 08C and CSA 7190 mg, 0.8 mmol) was
added with stirring. The resulting mixture was left for
10 min at 08C, allowed to warm to room temperature and
monitored by GC±MS. A solution of brine 7125 mL), satu-
rated NaHCO
the mixture, and the product extracted with Et
The organic layer was separated and washed with brine
and K CO 71:1), ®ltered
7125 mL) and H
O 7125 mL) were added to
2
3
O 7500 mL).
2
72£200 mL), dried over MgSO
4
2
3
and evaporated in vacuo to give a clear oil 71ꢀ.1 g).
Chromatography 7silica; hexanes/EtOAc/MeOH 60:35:5)
1
gave 2a 712 g, 58%) as a clear oil: R
2
4. Experimental
0.18 7hexanes/
f
EtOAc/MeOH 60:35:5); IR 7thin ®lm) 3462 7br), 2939,
28ꢀ0, 1455, 1350, 1125, 10ꢀ6, 1035, 988, 8ꢀ2, 814 cm ;
2
1
4
.1. General methods
1
H NMR 7CDCl , 300 MHz) d 1.19±1.6 7m, 8H, CH ), 2.91
3
2
1
13
H and C NMR spectra were recorded on a Bruker DRX-
7br, 1H, OH), 3.26±3.5ꢀ 7m, 16H, CH
O), 4.32 7t, Jˆ3 Hz,
1H, CH); C NMR 7CDCl , ꢀ5 MHz) d 19.ꢀ, 25.ꢀ, 30.8,
3
2
1
3
3
00, a JEOL GSX-2ꢀ0 or a Bruker AM-500 with NMR
1
3
solvent as the internal standard. Gel phase C NMR of
solvent-swollen gels 7in CD Cl ) were recorded on a Bruker
61.9, 62.4, 66.9, ꢀ0.6, ꢀ0.8, ꢀ0.8ꢀ, ꢀ0.92, ꢀ2.9, 99.2; MS
1
1
7CI) m/z 2ꢀ9 7[M1H] ), 296 7100%, [M1NH
12.05 min. The material was used directly in the next step
without further puri®cation.
] ); GC±MS
2
2
4
1
3
1
AM-500. C and H Gel Phase MAS NMR spectra were
recorded on a Bruker MSL-300. IR spectra were recorded
on a Mattson 5000 FT-IR spectrometer. Solid-state diffuse
re¯ectance FT-IR spectra were recorded either neat or as
KBr dispersions 7using a KBr background). Single bead
FT-IR spectra 7transmittance) were recorded on the ATI
Mattson 7In®nity series 60MI) Quantum FT-IR microscope.
GC±MS spectra were recorded on a Hewlett Packard
R
t
4.1.2. 2-+17-Bromo-3,6,9,12-tetraoxaheptadecan-1-lyoxy)-
tetrahydropyran +3a). Alcohol 2a 71.4g, 4. ꢀ mmol) in
THF 710 mL) was added dropwise to a suspension of NaH
7350 mg, 8.ꢀ mmol) in THF 730 mL) cooled in an ice bath.
The mixture was allowed to warm up to room temperature
and stirred for 3 h. Stirring was stopped and the supernatant
solution and THF washings 720 mL) were added slowly by
cannula to 1,5-dibromopentane 724.9 g, 110 mmol) with
stirring over 15 min. After the addition was complete, the
mixture slowly turned milky white and was left at room
temperature for 24h. The mixture was diluted with
5
890GC/59ꢀ2MS spectrometer 7helium; HP-5 capillary
column: 25 m length). The GC method was: 7T ˆ508C
o
2
1
7
2 min); T ˆ2508C 75 min); rateˆ208C min ). Bromine
f
and chlorine microanalyses were carried out at UCL
Analytical Services. ICP-AES analysis 7%Ti) was carried
out at the Geology Department at Imperial College on a
Fisons ARL3580B, 1m vacuum spectrometer. X-Ray photo-
electron spectroscopy was carried out at UCL. Electron
microscopy studies were performed on a JEOL JSM-T200
scanning electron microscope 7Materials Department,
Imperial College). Secondary electron images 7SEIs) were
recorded at an accelerating voltage of 15 kV and back-
scattered electron imaging 7BEI) at 15 or 25 kV. Qualitative
analysis of the samples was achieved by X-ray dispersive
spectrometry 7X-EDS), recorded by analysis of four or ®ve
beads at 25 kV accelerating voltage using the Link 290 EDX
microanalytical system. The polyethylene-containing
sample was analyzed on a JEOL JSM-T220A. The sample
was prepared by supporting on a cold mounting resin. The
resin hardener and cold mounting powder were thoroughly
CH
layer was extracted with CH
organic layers were washed with brine 7100 mL), dried over
Na SO , ®ltered and evaporated in vacuo. Chromatography
7silica; CH Cl /EtOAc/MeOH 90:9:1) gave 3a 71.04g,
52%) as a clear oil: R 0.23 7CH Cl /EtOAc/MeOH
90:9:1); IR 7thin ®lm) 2938, 286ꢀ, 1454, 1350, 1284,
Cl
2
7100 mL) and brine 7100 mL) and the aqueous
2
Cl
72£50 mL). The combined
2
2
2
4
2
2
f
2
2
2
1
1
1252, 1201, 1125, 10ꢀꢀ, 1035, 988, 8ꢀ2, ꢀ32 cm ; H
NMR 7CDCl , 300 MHz) d 1.43±2.3 712H, m, CH ±C),
3.32±3.82 7m, 22H, CH ±O and CH ±Br), 4.56 7t,
Jˆ3 Hz, 1H, O±CH±O); C NMR 7CDCl , ꢀ5 MHz) d
19.3, 24.ꢀ, 25.3, 28.6, 30.4, 32.4, 33.5 7CH ), 62.0, 66.5,
ꢀ0.0, ꢀ0.3, ꢀ0.47coincident), ꢀ0.8, ꢀ6.5, ꢀ6.9, ꢀꢀ.47CH
3
2
2
2
1
3
3
2
±
2
1
O), 98.ꢀ 7O±CH±O); MS 7CI) m/z 444, 446 7[M1NH ] );
4

A. G. M. Barrett, Y. R. de Miguel / Tetrahedron 58 +2002) 3785±3792
3ꢀ89
GC±MS R 18.49 min; HRMS 7CI) calcd for C H BrNO :
t
1526, 1491, 1445, 1350, 1204, 1120, 1029, 963, 909,
848 cm . Anal. found: C, 86.03; H, ꢀ.8ꢀ; N, 0.30
18 39
6
1
1
[M1NH ] ), 444.1961; found: 7[M1NH ] ), 444.2003.
21
7
Anal. calcd for C H BrO : C, 50.59, H, 8.25. Found: C,
4
4
2
70.21 mmol g ).
1
1
8
35
6
5
0.8ꢀ; H, 8.21.
4
.1.6. Sodium ethyltrimethylcyclopentadienide +8). A
9
4
.1.3. Polystyrene-supported THP ether +5a). p-Bromo-
solution of the tetraalkyl cyclopentadiene 70.4g, 3 mmol)
in THF 710 mL) was added slowly, by cannula, to an ice-
cooled suspension of NaH 70.19 g, 4.ꢀ mmol) in THF
710 mL). The mixture was stirred at room temperature for
4h and ®ltered by cannula for immediate use.
polystyrene 70.9ꢀ g, 1.0 mmol) and n-BuLi 72.5 M in
hexane; 3.3 mL, 8.2 mmol) in dry PhMe 720 mL) were
heated at 658C for 23 h. The solution was removed by
cannula and fresh PhMe and n-BuLi were added as before.
The mixture was further heated for 2ꢀ h. After removal
of the supernatant solution by cannula, the dark brown
polymer was washed thoroughly with PhMe and suspended
in PhMe. Bromide 3a 71.2 g, 2.8 mmol) in PhMe 75 mL)
was added by cannula to the slurry of polystyryllithium 4
in PhMe, and a fast color change to orange was observed.
The mixture was further stirred at 658C for 24h. The
4.1.7. Polystyrene-supported peralkylated cyclopenta-
diene +9). A solution of sodium ethyltrimethylcyclopenta-
dienide 8 70.06 M in THF, 15 mL, 0.9 mmol) was added
slowly, by cannula, to a suspension of polymer 7
70.21 mmol g, 0.14g, 0.03 mmol) in THF 71 mL). The
resulting mixture was shaken at room temperature for ꢀ
days, ®ltered and the polymer washed thoroughly with
H O, THF, MeOH, Me CO, EtOAc, CH Cl and pentane
polymer was ®ltered, washed thoroughly with H O,
2
MeOH, Me CO, EtOAc, CH Cl and pentane 7all 100 mL)
2
2
2
2
2
2
2
and dried in vacuo 7508C, 0.1 mm, 4days) to give 5a
0.ꢀ6 g) as orange beads: IR 7diffuse re¯ectance) 3060,
7all 50 mL) and dried in vacuo to give 9 791 mg) as brown
beads: IR 7solid-state, diffuse re¯ectance, neat) 3059,
3028, 2923, 2852, 1944, 18ꢀ2, 1803, 1ꢀ45, 166ꢀ, 1601,
1492, 1449, 13ꢀ1, 1328, 1184, 1115, 10ꢀ0, 1028, 90ꢀ,
7
3
1
9
029, 2923, 2888, 2849, 1945, 18ꢀ3, 1803, 1ꢀ46, 1601,
491, 1450, 1366, 1325, 1248, 1183, 1123, 10ꢀ3, 1029,
0ꢀ, 839, ꢀ60 cm ; H NMR 7CDCl , 300 MHz, gel
2
1
1
21
841 cm ; IR 7solid-state, transmittance, polystyrene
background) 1600, 1492, 1453, 136ꢀ, 1244, 1185, 1122,
3
phase MAS) d 1.58, 1.99, 3.ꢀ6 7CH O), 5.60 7br), 5.99,
2
1
.15, 6.4ꢀ, 6.64, 6.65, 6.68, ꢀ.15; C NMR 7125 MHz,
3
21
1028, 842, ꢀꢀ2 cm ; IR and FAR-IR 7diffuse re¯ectance,
6
CD Cl , gel phase MAS) d 14.2, 14.3, 20.0, 22.ꢀ, 25.9,
CsI dispersion) 1598, 1494, 145ꢀ, 1382, 1315, 1182, 10ꢀ2,
102ꢀ, 966, 906, 840, ꢀꢀ1, ꢀ0ꢀ, 620 and 541 cm ; H NMR
2
2
2
1 1
3
9
0
0.1, 31.1, 34.5, 40.9, 43±45, 6ꢀ.2, ꢀ0.ꢀ 7strong, C±O),
9.5, 126.1, 128.2. Anal. found: C, 86.50; H, ꢀ.88; N,
.00; Br, 3.96.
7CDCl , 300 MHz, gel phase MAS) 20.33, 0.03, 0.24, 1.58,
3
1
3.41 and 6.ꢀ2; C NMR 7CDCl , ꢀ5 MHz, gel phase MAS)
3
3
0.9, 14.ꢀ, 23.1, 26.4, 30.2, 41.1, 42.4, 44.3, 102.ꢀ, 120.0,
126.3, 128.4, 146.0, 151.8, 153.9, 1ꢀ1.6, 1ꢀ9.6. Anal. found:
4
.1.4. Polystyrene-supported alcohol resin +6). A mixture
2
C, 8ꢀ.06; H, ꢀ.12; N, 0.0 70.21 mmol g ).
1
of polymer 5a 70.35 g, 0.35 mmol) and CSA 70.28 g,
.2 mmol) in THF 710 mL) and H O 70.5 mL) was shaken
1
2
at room temperature for 5 days, ®ltered and thoroughly
washed with H O, aqueous MeOH, MeOH, Me CO,
EtOAc, CH Cl and pentane 7all 100 mL), and dried in
4.1.8. 2-+1-Naphthyl)-3,4-dihydro-2H-pyran +1b). 1-Iodo-
naphthalene 72.5 mL, 11.5 mmol), dihydropyran 1a 71ꢀ mL,
186 mmol), Et N 73.4mL, 25.4mmol) and 7Ph P) PdCl
2
2
2
2
2
3
3
2
vacuo to give 6 70.31 g) as a pale yellow solid: IR 7solid-
state) 34ꢀ3 7br), 3064, 3022, 2922, 2889, 2843, 1942, 18ꢀ3,
7208 mg, 0.28 mmol, 2 mol%) were degassed 7freeze-
pump-thaw twice) and heated in a sealed tube at 1008C
for 48 h. GC±MS analysis showed no starting material
and a mixture of isomeric products. The cooled reaction
mixture was extracted with CH Cl 750 mL), washed with
1
1
ꢀ
803, 1ꢀ45, 1666, 1601, 1543, 1489, 1446, 13ꢀ5, 1329,
246, 1182, 1153, 1111, 10ꢀ2, 1030, 964, 906, 841, ꢀ5ꢀ,
00, 690, 54ꢀ, 532 cm ; H NMR 7CDCl , 300 MHz, gel
2
1 1
3
2
2
phase MAS) d 0.13, 0.15, 1.59, 2.01, 3.59, 3.ꢀ3, 3.ꢀ9
H O 72£50 mL) and the organic extracts were evaporated in
2
1
CH O), 6.65, ꢀ.16; C NMR 7CDCl , ꢀ5 MHz, gel phase
3
7
MAS) d 0.8, 14.9, 23.2, 26.ꢀ, 30.3, 32.3, 34.4, 36.3, 41.2,
vacuo to give an orange oil. The crude product was redis-
solved in pentane, ®ltered, evaporated in vacuo and
chromatographed 7silica, pentane) to give 1b/1c 72.43 g,
100%). Chromatography 7silica, pentane) gave isomer 1b
2
3
4
1
1
2.6, 44.6, 46.8, 62.4, ꢀ1.4 7strong, C±O), ꢀ2.3, ꢀ3.5, 80.9,
00.8, 104.0, 104.9, 118.1, 140.4, 146.1, 154.2, 156.4,
68.2, 1ꢀ3.8. Anal. found: C, 86.58; H, ꢀ.93; N, 0.00.
71.4g, 58%) as a clear oil: R 0.18 7pentane); IR 7thin
f
2
lm) 305ꢀ, 2922, 164ꢀ, 1240, 1058, ꢀ9ꢀ, ꢀꢀ9, ꢀ32 cm ;
H NMR 7CDCl , 300 MHz) d 2.0±2.4 7m, 4H), 4.86 7m,
3
1
®
1
4
.1.5. Polystyrene-supported 4-nitrobenzenesulfonate
resin +7). Pyridine 70.2 mL, 2.5 mmol) was added dropwise
to a mixture of polymer 6 70.22 g, 0.2 mmol) and 4-nitro-
benzenesulfonyl chloride 718ꢀ mg, 0.84mmol) in CH Cl
1H), 5.55 7d, Jˆ9 Hz, 1H), 6.647d, Jˆ6 Hz, 1H), ꢀ.2±8.0
1
7ꢀH, m, ꢀH, ArH); C NMR 7CDCl , ꢀ5 MHz) d 21.3, 30.1,
3
3
ꢀ4.8, 101.3, 123.4, 123.ꢀ, 125.9, 126.5, 128.6, 129.4 7ꢀ Ar
CH), 130.8, 134.2, 13ꢀ.8 73 Ar C), 145.0; MS 7CI) m/z 211
2
2
7
3
10 mL). The mixture was shaken at room temperature for
days, ®ltered and the polymer washed thoroughly with
H O, THF, MeOH, Me CO, EtOAc, CH Cl and pentane
1
1
786%, [M1H] ), 228 7100%, [M1NH ] ); GC±MS R
4 t
1
11.ꢀ4min; HRMS 7CI) calcd for C H O1H: 7[M1H] ),
2
2
2
2
15 14
1
211.1123; found: 7[M1H] ), 211.1114. Anal. calcd for
7
all 50 mL), dried in vacuo to give 6/7 7200 mg) as pale
yellow beads. The polymer was allowed to react again
with 4-nitrobenzenesulfonyl chloride 7200 mg, 0.9 mmol)
and pyridine 70.2 mL, 2.5 mmol) in CH Cl 720 mL) and
further shaken for 5 days. The polymer 7 was puri®ed as
before to give pale brown beads 71ꢀ0 mg): IR 7solid-state)
C H O: C, 85.68, H, 6.ꢀ1. Found: C, 85.84; H, 6.91.
14
1
5
4.1.9. 2-+1-Naphthyl)-3,6-dihydro-2H-pyran +1c). 1-Iodo-
naphthalene 70.6 mL, 4.1 mmol), 3,4-dihydropyran 1a 74mL,
44 mmol), Et N 70.8 mL, 5.ꢀ mmol) and bis7triphenyl-
2
2
3
3
0ꢀ1, 303ꢀ, 28ꢀ5, 1946, 18ꢀ4, 1803, 1ꢀ4ꢀ, 1669, 1600,
phosphine)palladium diacetate 744 mg, 0.06 mmol, 1 mol%)

3ꢀ90
A. G. M. Barrett, Y. R. de Miguel / Tetrahedron 58 +2002) 3785±3792
were degassed 7freeze-pump-thaw twice) and heated in a
sealed tube at 1008C for 24h. The cooled reaction mixture
was extracted with CH Cl 730 mL), washed with H O
72£50 mL), and the organic extracts were evaporated in
vacuo to give an orange oil. Chromatography 7silica,
diastereoisomers. The partial separation of the diastereo-
isomers 7R 0.61, 0.69 7hexanes/EtOAc/MeOH 60:35:5))
f
was achieved giving samples of each both as clear oils.
The less polar isomer of 3b 7R 0.61) showed: IR 7thin
2
2
2
f
®lm) 3050, 2938, 2863, 159ꢀ, 1455, 1350, 1296, 1241,
1202, 1118, 10ꢀ3, 1029, 983, 859, 800, ꢀꢀ9, ꢀ35 cm ; H
2
1 1
pentane) gave isomer 1c 70.3ꢀ g, 42%) as a clear oil: Rf
0
1
ꢀ
2
1
.09 7pentane); IR 7thin ®lm) 3038, 2926, 2824, 1655,
59ꢀ, 1511, 1388, 1338, 1235, 11ꢀ9, 1091, 1023, 919,
99, ꢀꢀꢀ, 659 cm ; H NMR 7CDCl , 300 MHz) d 2.32±
NMR 7CDCl , 300 MHz) d 1.18±1.96 7m, 12H), 3.30±3.95
3
7m, 20H), 4.ꢀ2 7dd, Jˆ2.0, 9.5 Hz, 1H), 5.08 7dd, Jˆ9.ꢀ Hz,
2
1
1
13
1H), ꢀ.19±ꢀ.96 7m, ꢀH, ArH); C NMR 7CDCl , ꢀ5 MHz)
3
3
.55 7m, 2H), 4.32±4.48 7m, 2H), 5.20 7dd, Jˆ3.ꢀ, 9.4Hz,
d 23.8, 25.8, 29.ꢀ, 32.1, 32.9, 33.5, 34.6, 68.8, ꢀ1.1, ꢀ1.5
7coincident), ꢀ2.0, ꢀ5.8, 104.2, 124.1, 126.2, 126.5, 126.ꢀ,
128.8, 129.8; MS 7CI) m/z 210 7100%, M2343), 5ꢀ2 7ꢀ1%,
1
H), 5.ꢀ9±5.96 7m, 2H), ꢀ.34±8.05 7m, ꢀH, ArH); C NMR
3
7
CDCl , ꢀ5 MHz) d 30.ꢀ, 65.3, ꢀ1.ꢀ, 121.8, 122.0, 123.3,
3
1
1
24.0, 124.1, 124.5, 125.0, 126.6, 12ꢀ.4 7ꢀ Ar12 alkene
CH), 129.1, 132.3, 136.6 73 Ar C); MS 7CI) m/z 211
[M1NH ] ); HRMS 7CI) calcd for C H NO Br:
28 45
4
6
1
7[M1NH ] ), 5ꢀ2.2439, 5ꢀ0.2450; found: 7[M1NH ] ),
1
4
4
1
5ꢀ%, [M1H] ), 228 7100%, [M1NH ] ); GC±MS R
1
1
7
5ꢀ2.2410, 5ꢀ0.2430. Anal. calcd for C H BrO : C,
28 41 6
60.ꢀ6, H, ꢀ.4ꢀ. Found: C, 60.4ꢀ; H, ꢀ.20.
4
t
1
1.88 min; HRMS 7CI) calcd for C H O1H: 7[M1H] ),
1
5
14
1
11.1123; found: 7[M1H] ), 211.1125. Anal. calcd for
2
C H O: C, 85.68; H, 6.ꢀ1. Found: C, 85.49; H, 6.91.
4.1.12. Polystyrene-supported ether +5b). p-Bromopoly-
styrene 72.11 g, 2.1 mmol) and n-BuLi 72.5 M in hexane,
8.0 mL, 1ꢀ.6 mmol) in PhMe 730 mL) were heated at
658C for 28 h. The solution was removed by cannula and
fresh PhMe and n-BuLi were added as before. The mixture
was heated for 26 h, washed, re-treated with fresh reagents
and the resulting dark polymer suspension was heated for a
further 24h. After removal of the supernatant solution by
cannula, the dark brown-red lithiated polymer was washed
thoroughly with dry PhMe 72£10 mL) and suspended in
PhMe. A solution of the bromide 3b 71.0 g, 1.81 mmol) in
PhMe 75 mL) was added by cannula to the slurry of poly-
styryllithium 4 in PhMe, and a gradual color change to
orange was observed. The mixture was heated at 658C for
42 h and was left at room temperature for 24 h. The polymer
was ®ltered, washed thoroughly with H O, MeOH, Me CO,
1
5
14
4.1.10. 3,6,9,12-Tetraoxa-12-+2-+6-+1-naphthyl))-2-tetra-
hydropyran-1-yl)-dodecan-1-ol +2b). Dry CSA 7200 mg,
0
1
.8 mmol) was added to crude 2-naphthyl-dihydropyran
b and 1c 72.5 g, 11.5 mmol) and tetraethylene glycol
7
5.5 mL, 32 mmol) in CH Cl 740 mL), The resulting
2 2
mixture was left at room temperature overnight. The
mixture was washed with brine, saturated aqueous
NaHCO3 and H O 720 mL each) and extracted with
2
CH Cl2 72£20 mL). The organic layer was separated,
2
washed with brine 730 mL), dried over MgSO , ®ltered
4
and evaporated in vacuo gave 2b as a mixture of diastereo-
isomers. Chromatography 7silica, hexanes/EtOAc/MeOH
6
Rf 0.147hexanes/EtOAc/MeOH 65:30:5); IR 7thin ®lm)
5:30:5) to give 2b 72.93 g, 64% from 1a) as a clear oil:
2
2
3
1
3
3
1
465 7br), 3050, 293ꢀ, 28ꢀ2, 159ꢀ, 1511, 1455, 1350,
EtOAc, CH Cl and pentane 7all 100 mL) and dried in vacuo
2 2
21 1
122, 10ꢀ2, 103ꢀ, 982, 801, ꢀ80 cm ; H NMR 7CDCl ,
7508C, 0.1 mm, 24h) to give 5b 71.85 g) as orange beads: IR
7diffuse re¯ectance) 30ꢀ8, 3062, 3024, 2939, 2908, 2848,
1944, 18ꢀ3, 1803, 1ꢀ45, 1666, 1601, 1495, 1452, 13ꢀ3,
1329, 1246, 1180, 1155, 1115, 10ꢀ2, 1028, 964, 943, 906,
3
00 MHz) d 1.ꢀ1±2.01 7m, 6H), 2.ꢀ3 7br, 1H, OH), 3.56±
.9 7m, 16H, 8£CH O), 5.12 7s, 1H), 5.60 7dd, Jˆ2, 11 Hz,
2
1
H), ꢀ.26±8.147m, ꢀH, ArH); C NMR 7CDCl , ꢀ5 MHz)
3
3
2
1 1
d 18.4, 29.8, 33.2, 61.8, 66.ꢀ, 68.1, ꢀ0.4, ꢀ0.ꢀ 7coincident
CH O), ꢀ2.5, 98.4, 123.3, 123.4, 125.3, 125.6, 125.ꢀ, 12ꢀ.6,
839, 621, 542 cm ; H NMR 7CDCl , 300 MHz, gel phase
3
1
MAS) d 0.11, 0.13, 1.58, 1.98, 3.ꢀ3 7CH O), 6.64, ꢀ.15; C
3
2
2
1
28.9, 130.5, 133.8, 139.0; MS 7CI) m/z 422 7100%,
M1NH ] ); HRMS calcd for [C H O 1NH ]:
Gel NMR 7125 MHz, CD Cl ) d 0.8, 15.0, 23.2, 30.4, 41.2,
2
2
1
1
[
44.6, 46.ꢀ, ꢀ1.4 7strong, C±O), ꢀ3.3, 81.3, 99.1, 101.4,
104.1, 126.4, 128.5, 128.ꢀ, 146.02, 156.0, 1ꢀ3.4. Anal.
found: C, 86.ꢀ8; H, ꢀ.6ꢀ; Br, 4.13.
4
23 32
6
4
1
[M1NH ] ), 422.25426; found: 7[M1NH ] ), 422.2538.
1
7
Anal. calcd for C H O : C, 68.28, H, ꢀ.98. Found: C,
4
4
2
3
32
6
6
8.11; H, ꢀ.85.
4.1.13. Procedure for UV monitoring of the deprotection
4
.1.11. 2-+17-Bromo-3,6,9,12-tetraoxaheptadecan-1-yl-
of resin 5b: estimated loading level of alcohol resin 6. The
protected polymer 5b 71.21 g, 1.2 mmol) and CSA 70.89 g,
3.8 mmol) in THF 710 mL) and EtOH 7ꢀ mL) were shaken
at room temperature for 24h. The polymer was ®ltered off
and thoroughly washed with THF 710 mL). Saturated
aqueous NaHCO3 solution was added dropwise to the
oxy)-6-+1-naphthyl)-tetrahydropyran +3b). Alcohol 2b
2.3ꢀ g, 5.8 mmol) in THF 750 mL) was added dropwise
7
to an ice-cooled suspension of NaH 70.65 g, 16 mmol) in
THF 750 mL). The resulting mixture was allowed to warm
to room temperature and stirred for 20 h. The supernatant
solution was decanted by cannula and added dropwise to
®ltrate until ®zzing stopped and Et O 730 mL) was added.
2
1
,5-dibromopentane 725 mL, 183 mmol). The solution went
The aqueous layer was further extracted with Et O
2
cloudy and NaBr precipitated overnight. The mixture was
diluted with CH Cl and H O, and the aqueous layer was
72£30 mL) and the combined organic layers were dried
over Na SO , ®ltered and evaporated in vacuo to give a
4
2
2
2
2
extracted with CH Cl 72£25 mL). The combined organic
solid residue 725 mg); UV lmax 7MeCN) 222 nm 7absorb-
ance corresponding to 0.1 mmol). Loading level ca.
2
2
layers were washed with brine 72£25 mL), dried over
2
1
Na SO , ®ltered and evaporated in vacuo. The crude oil
2
0.1 mmol g . The polymer was washed thoroughly with
H O, MeOH, Me CO, EtOAc, CH Cl and pentane 7all
4
was ®ltered through a large plug of silica with CH Cl to
2
2
2
2
2
2
remove excess 1,5-dibromopentane and with EtOAc to yield
b as a clear oil. Chromatography 7silica; hexanes/EtOAc/
MeOH 60:35:5) gave 3b 71.ꢀ4g, 5 4% ) as a mixture of
100 mL) and dried in vacuo 7508C, 0.1 mm, 24h) to give
polymer 6 71.12 g): IR 7solid-state) 3400 7br), 30ꢀ2, 304ꢀ,
3002, 295ꢀ, 2922, 2843, 1945, 18ꢀ4, 1804, 1ꢀ44, 16ꢀ3,
3

A. G. M. Barrett, Y. R. de Miguel / Tetrahedron 58 +2002) 3785±3792
3ꢀ91
1
9
599, 1542, 1464, 13ꢀ5, 1312, 1183, 1154, 10ꢀ0, 964, 943,
08, 844, ꢀꢀꢀ cm ; H NMR 7CDCl , 300 MHz, gel phase
temperature overnight. Filtration through a short pad of
silica 7CH Cl ) and evaporation in vacuo gave 11b
2
1 1
3
2
2
MAS) d 20.3ꢀ, 0.16, 1.04, 1.60, 2.01, 3.ꢀ8 7CH O), 6.65,
2
742 mg, 8ꢀ%), a mixture of isomers 73:1), as a white
solid: mp 105±1098C; R 0.ꢀ6 71:1 Et O/pentane); IR
1
.18; C NMR 7CDCl , ꢀ5 MHz) d 0.8, 14.9, 23.1, 29.6,
3
ꢀ
3
1
1
3
f
2
6.3, 41.1, 42.4, 44.4, 62.4, 69.3, ꢀ1.3 7C±O), 99.6, 10ꢀ.2,
12.9, 11ꢀ.1, 120.5, 126.4, 128.4, 146.0, 15ꢀ.3, 1ꢀ4.9,
ꢀ9.4. Anal. found: C, 8ꢀ.96; H, ꢀ.48; N, 0.00.
7CH Cl ®lm) 3056, 29ꢀꢀ, 293ꢀ, 1ꢀ68, 1ꢀ12, 1599, 1501,
2 2
2
1
1
1442, 1401, 1266, 1141, ꢀ93, ꢀ38 cm ; H NMR 7500
MHz, CDCl ) d 0.68 7d, Jˆ6.5 Hz, 3H, bridgehead Me,
3
ꢀ
2%), 0.98 7d, Jˆ6.ꢀ Hz, 3H, bridgehead Me, 28%),1.5ꢀ
4.1.14. Characterization of cleavage product from poly-
mer 5b: 2-ethoxy-6-+1-naphthyl)-tetrahydropyran +1e).
7q, Jˆ6.5 Hz, 1H, bridgehead H, 28%), 1.ꢀ3±1.ꢀ8 7m,
12H, 4Me), 2.13 71H, q, Jˆ6.5 Hz, bridgehead H, ꢀ2%),
1
3
Polymer 5b 71.02 g, 2.5 mmol) and CSA 71.6 g, ꢀ mmol)
in THF 760 mL) and H O 72 mL) were stirred at room
ꢀ.30±ꢀ.43 75H, m, ArH); C NMR 7CDCl3, 125 MHz) d
ꢀ.9, 9.2, 10.9, 11.1, 12.9, 13.2, 29.ꢀ, 30.4, 60.4, 61.0, ꢀ8.ꢀ,
ꢀ9.9, 125.4, 128.0, 128.1, 129.0, 131.6, 131.8, 135.5, 159.2,
2
temperature for 24h. GC±MS analysis showed two
products: dihydropyran 1b 738%, M 210) and tetrahydro-
1
z
1
159.6; MS 7CI) m/z 312 766%, [M1H] ), 136 7100%, Cp);
HRMS 7CI) calcd for C H N O : 7[M1H] ), 312.1ꢀ12;
1
z
1
pyran 1d 75ꢀ%, M 228). EtOH 710 mL) was added to the
reaction mixture and the solution was left standing for 2 h.
At this stage the only product detected by GC±MS was ether
1
8
21
3
2
1
found: 7[M1H] ), 312.1ꢀ00. Anal. calcd for C H N O :
1
8
21
3
2
C, 69.43; H, 6.80; N, 13.49. Found: C, 69.34; H, ꢀ.01; N,
13.ꢀ9.
1
z
1
was added until the effervescence stopped, and Et O
e 7100%, M 256). Saturated aqueous NaHCO solution
3
2
7
with Et O 730 mL) and the combined organic layers were
30 mL) was added. The aqueous layer was further extracted
4.1.17. Polystyrene-supported titanocene dichloride
complex +12). Polymer 9 70.11 mmol g , 1.08 g, 0.12
2
1
2
dried over Na SO , ®ltered and evaporated in vacuo to give
2
mmol) was suspended in THF 710 mL) and MeLi 71.5 M
in Et O, 0.6 mL, 0.9 mmol) was added dropwise. The result-
4
1
Et O/hexanes 5:95) gave samples of the two isomers as
e 70.63 g, 98%) as an oil. Chromatography 7silica, hexanes;
2
ing mixture was shaken at room temperature for 3 days
when the supernatant solution was removed by cannula.
The beads were thoroughly washed with THF 710 mL)
and PhMe 72£10 mL). Cyclopentadienyltitanium trichloride
754mg, 0.25 mmol) in PhMe 710 mL) was added by cannula
to the beads in PhMe 710 mL) and the suspension was
shaken at room temperature for 6 days. The solution was
completely removed as before and the resin was thoroughly
washed with THF 72£40 mL) and PhMe 72£40 mL) and
dried in vacuo overnight to give 12 70.88 g) as orange-
brown beads: TGA: residue 8.18%; IR and FAR-IR 7diffuse
re¯ectance, CsI dispersion) 1598, 1494, 1454, 129ꢀ, 1201,
1155, 1112, 1066, 1025, 9ꢀꢀ, 944, 906, ꢀ38, ꢀ00, 534, 464,
2
white solids R 0.26, 0.30 7pentane). The more polar isomer
f
showed: mp 64±658C; IR 7CH Cl ®lm) 3052, 29ꢀꢀ, 294ꢀ,
2
2
1
ꢀ
3ꢀ2, 1266, 1125, 1064, 1029, 981, 801, ꢀ80, ꢀ39,
2
05 cm ; UV l
1
1
7MeCN) 224nm 7 1 ꢀ6,000); H NMR
max
7
7
CDCl , 400 MHz) d 1.28 7t, Jˆꢀ Hz, 1H, Me), 1.ꢀ2±2.25
3
m, 6H), 3.547m, 1H, methylene), 3.82 7m, 1H, methylene),
5
ꢀ
3
1
.12 7br s, 1H), 5.61 7dd, Jˆ2, 11 Hz, 1H), ꢀ.46±8.15 7m,
1
H, ArH); C NMR 7CDCl , 125 MHz) d 15.3, 18.9, 30.0,
3
3
3.2, 62.ꢀ, 6ꢀ.9, 9ꢀ.8, 123.2, 123.4, 125.3, 125.ꢀ, 125.8,
2ꢀ.ꢀ, 129.0, 130.4, 133.8, 139.0; MS 7CI) m/z 2ꢀ479%,
1
1
1
[
GC±MS R 11.98 min; HRMS 7CI) calcd for C H NO :
M1NH ] ), 256 732%, M ), 228 7100%, [M1H2Et] );
4
t
1ꢀ 24
2
1
[M1NH ] ), 2ꢀ4.180ꢀ; found: 7[M1NH ] ), 2ꢀ4.1805.
1
21 1
7
Anal. calcd for C H O : C, ꢀ9.65, H, ꢀ.86. Found: C,
325, 264, 233, 208 cm ; H NMR 7CDCl , 300 MHz, gel
3
4
4
phase MAS) d 0.12, 0.14, 0.32, 1.56, 1.98, 2.45, 6.62, ꢀ.15;
C Gel NMR 7125 MHz, CD Cl ) d 0.8, 12.8, 14.9, 22.3,
2 2
1
ꢀ
20
2
1
3
ꢀ
9.59; H, ꢀ.86.
41.1, 44.5, 69.2 7C±O), 99.8, 100.9, 118.3, 126.4, 128.5,
146.0, 156.2, 1ꢀ3.ꢀ. Anal. found: C, 85.66; H, ꢀ.53; X
4.1.15. Polystyrene-supported Diels±Alder adduct +11a).
Cookson's reagent 10 75 mg, 29 mmol) in CH Cl 70.25 mL)
2
7Br, Cl), 5.90; N, 0.00; Ti, 0.33 70.0ꢀ mmol g Ti).
1
2
2
was added dropwise to a cooled suspension of cyclopenta-
diene polymer 9 710 mg, 2 mmol) in CH Cl 70.25 mL). The
2
2
resulting mixture was left at room temperature overnight,
saturated aqueous NaHCO solution was added and the
4.2. Catalytic activity of polymer-supported titanocene
dichloride +12) in the polymerization of ethene:
preparation of polyethylene +PE)
3
polymer was collected by ®ltration, washed thoroughly
with H O, THF, MeOH, Me CO, EtOAc, CH Cl and pen-
tane 7all 50 mL) and dried in vacuo to give 11a 78 mg) as
2
2
2
2
Excess MAO 71.ꢀ2 M in PhMe, 10 mL, 1ꢀ mmol) was
added to a suspension of catalyst beads 12 70.25 g,
1ꢀ.5 mmol) in PhMe 750 mL) and the mixture was stirred
for 30 min. Ethylene gas was added to the evacuated
mixture at 208C. The polymerization reaction was stopped
after 1 h, as no more polymer appeared to be formed. The
MAO was destroyed with a 10% HCl in MeOH, and the
brown beads: IR 7solid-state, transmittance, neat) 3060,
3
1
029, 2932, 2853, 1944, 18ꢀ2, 1ꢀ22, 1602, 1494, 1449,
3ꢀ1, 1239, 1116, 10ꢀ1, 1028, 90ꢀ, 840 cm ; IR 7solid-
2
1
state, transmittance, polystyrene background) 1ꢀ11, 1645,
2
558, 140ꢀ, 1236, 1128 cm . Anal. found: C, 82.45; H,
1
1
ꢀ
2
.13; N, 1.1ꢀ 70.28 mmol g ).
1
polymer was ®ltered and washed thoroughly with Me CO.
2
4
.1.16. Diels±Alder reaction of N-phenyl-1,3,4-triazo-
line-2,5-dione 10 with pentamethylcyclopentadiene.
After drying in vacuo at 508C overnight, the product poly-
ethylene±polystyrene 70.9ꢀ g) was obtained as a brown
solid. This represents a mass of polyethylene of 0.ꢀ2 g
Cookson's reagent 10 72ꢀ mg, 154 mmol) in CH Cl
2
70.ꢀ5 mL) was added dropwise to a solution of pentamethyl-
cyclopentadiene 721.8 mg, 160 mmol) in CH Cl 70.25 mL)
2
2
1
which corresponded to a catalytic activity of 41 g mmol
bar h . DSC: T 142.258C, T 169.488C, T 450.348C;
2
1
21
2
2
1
2
3
at 2ꢀ88C. The dark red color disappeared almost imme-
diately and the resulting yellow solution was left at room
GPC 7ꢀ mg in 25 mL trichlorobenzene, 1608C): Mn
358,000, M 8ꢀ2,000, M /M 2.4; peak ꢀ34,000.
w
w
n

3ꢀ92
A. G. M. Barrett, Y. R. de Miguel / Tetrahedron 58 +2002) 3785±3792
3. Winter, M. Supports for Solid-phase Organic Synthesis. In
Acknowledgements
Combinatorial Peptide and Nonpeptide Libraries, Jung, G.,
Ed.; VCH: Weinheim, 1996; p 465.
We thank Professor Vernon C. Gibson and Brian Kimberley
Imperial College) for carrying out the catalytic assay of 12
7
4. 7a) Abbenhuis, H. C. L. Angew. Chem., Int. Ed. Engl. 1999, 38,
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Wolfson Foundation for establishing the Wolfson Centre
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